/*
 * Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 *
 *
 */

package javax.xml.transform.stream;

import java.io.File;
import java.io.InputStream;
import java.io.Reader;

import javax.xml.transform.Source;

/**
 * <p>Acts as an holder for a transformation Source in the form of a stream of XML markup.</p>
 *
 * <p><em>Note:</em> Due to their internal use of either a {@link Reader} or {@link InputStream}
 * instance, <code>StreamSource</code> instances may only be used once.</p>
 *
 * @author <a href="Jeff.Suttor@Sun.com">Jeff Suttor</a>
 */
public class StreamSource implements Source {

  /**
   * If {@link javax.xml.transform.TransformerFactory#getFeature}
   * returns true when passed this value as an argument,
   * the Transformer supports Source input of this type.
   */
  public static final String FEATURE =
      "http://javax.xml.transform.stream.StreamSource/feature";

  /**
   * <p>Zero-argument default constructor.  If this constructor is used, and
   * no Stream source is set using
   * {@link #setInputStream(java.io.InputStream inputStream)} or
   * {@link #setReader(java.io.Reader reader)}, then the
   * <code>Transformer</code> will
   * create an empty source {@link java.io.InputStream} using
   * {@link java.io.InputStream#InputStream() new InputStream()}.</p>
   *
   * @see javax.xml.transform.Transformer#transform(Source xmlSource, Result outputTarget)
   */
  public StreamSource() {
  }

  /**
   * Construct a StreamSource from a byte stream.  Normally,
   * a stream should be used rather than a reader, so
   * the XML parser can resolve character encoding specified
   * by the XML declaration.
   *
   * <p>If this constructor is used to process a stylesheet, normally
   * setSystemId should also be called, so that relative URI references
   * can be resolved.</p>
   *
   * @param inputStream A valid InputStream reference to an XML stream.
   */
  public StreamSource(InputStream inputStream) {
    setInputStream(inputStream);
  }

  /**
   * Construct a StreamSource from a byte stream.  Normally,
   * a stream should be used rather than a reader, so that
   * the XML parser can resolve character encoding specified
   * by the XML declaration.
   *
   * <p>This constructor allows the systemID to be set in addition
   * to the input stream, which allows relative URIs
   * to be processed.</p>
   *
   * @param inputStream A valid InputStream reference to an XML stream.
   * @param systemId Must be a String that conforms to the URI syntax.
   */
  public StreamSource(InputStream inputStream, String systemId) {
    setInputStream(inputStream);
    setSystemId(systemId);
  }

  /**
   * Construct a StreamSource from a character reader.  Normally,
   * a stream should be used rather than a reader, so that
   * the XML parser can resolve character encoding specified
   * by the XML declaration.  However, in many cases the encoding
   * of the input stream is already resolved, as in the case of
   * reading XML from a StringReader.
   *
   * @param reader A valid Reader reference to an XML character stream.
   */
  public StreamSource(Reader reader) {
    setReader(reader);
  }

  /**
   * Construct a StreamSource from a character reader.  Normally,
   * a stream should be used rather than a reader, so that
   * the XML parser may resolve character encoding specified
   * by the XML declaration.  However, in many cases the encoding
   * of the input stream is already resolved, as in the case of
   * reading XML from a StringReader.
   *
   * @param reader A valid Reader reference to an XML character stream.
   * @param systemId Must be a String that conforms to the URI syntax.
   */
  public StreamSource(Reader reader, String systemId) {
    setReader(reader);
    setSystemId(systemId);
  }

  /**
   * Construct a StreamSource from a URL.
   *
   * @param systemId Must be a String that conforms to the URI syntax.
   */
  public StreamSource(String systemId) {
    this.systemId = systemId;
  }

  /**
   * Construct a StreamSource from a File.
   *
   * @param f Must a non-null File reference.
   */
  public StreamSource(File f) {
    //convert file to appropriate URI, f.toURI().toASCIIString()
    //converts the URI to string as per rule specified in
    //RFC 2396,
    setSystemId(f.toURI().toASCIIString());
  }

  /**
   * Set the byte stream to be used as input.  Normally,
   * a stream should be used rather than a reader, so that
   * the XML parser can resolve character encoding specified
   * by the XML declaration.
   *
   * <p>If this Source object is used to process a stylesheet, normally
   * setSystemId should also be called, so that relative URL references
   * can be resolved.</p>
   *
   * @param inputStream A valid InputStream reference to an XML stream.
   */
  public void setInputStream(InputStream inputStream) {
    this.inputStream = inputStream;
  }

  /**
   * Get the byte stream that was set with setByteStream.
   *
   * @return The byte stream that was set with setByteStream, or null if setByteStream or the
   * ByteStream constructor was not called.
   */
  public InputStream getInputStream() {
    return inputStream;
  }

  /**
   * Set the input to be a character reader.  Normally,
   * a stream should be used rather than a reader, so that
   * the XML parser can resolve character encoding specified
   * by the XML declaration.  However, in many cases the encoding
   * of the input stream is already resolved, as in the case of
   * reading XML from a StringReader.
   *
   * @param reader A valid Reader reference to an XML CharacterStream.
   */
  public void setReader(Reader reader) {
    this.reader = reader;
  }

  /**
   * Get the character stream that was set with setReader.
   *
   * @return The character stream that was set with setReader, or null if setReader or the Reader
   * constructor was not called.
   */
  public Reader getReader() {
    return reader;
  }

  /**
   * Set the public identifier for this Source.
   *
   * <p>The public identifier is always optional: if the application
   * writer includes one, it will be provided as part of the
   * location information.</p>
   *
   * @param publicId The public identifier as a string.
   */
  public void setPublicId(String publicId) {
    this.publicId = publicId;
  }

  /**
   * Get the public identifier that was set with setPublicId.
   *
   * @return The public identifier that was set with setPublicId, or null if setPublicId was not
   * called.
   */
  public String getPublicId() {
    return publicId;
  }

  /**
   * Set the system identifier for this Source.
   *
   * <p>The system identifier is optional if there is a byte stream
   * or a character stream, but it is still useful to provide one,
   * since the application can use it to resolve relative URIs
   * and can include it in error messages and warnings (the parser
   * will attempt to open a connection to the URI only if
   * there is no byte stream or character stream specified).</p>
   *
   * @param systemId The system identifier as a URL string.
   */
  public void setSystemId(String systemId) {
    this.systemId = systemId;
  }

  /**
   * Get the system identifier that was set with setSystemId.
   *
   * @return The system identifier that was set with setSystemId, or null if setSystemId was not
   * called.
   */
  public String getSystemId() {
    return systemId;
  }

  /**
   * Set the system ID from a File reference.
   *
   * @param f Must a non-null File reference.
   */
  public void setSystemId(File f) {
    //convert file to appropriate URI, f.toURI().toASCIIString()
    //converts the URI to string as per rule specified in
    //RFC 2396,
    this.systemId = f.toURI().toASCIIString();
  }

  //////////////////////////////////////////////////////////////////////
  // Internal state.
  //////////////////////////////////////////////////////////////////////

  /**
   * The public identifier for this input source, or null.
   */
  private String publicId;

  /**
   * The system identifier as a URL string, or null.
   */
  private String systemId;

  /**
   * The byte stream for this Source, or null.
   */
  private InputStream inputStream;

  /**
   * The character stream for this Source, or null.
   */
  private Reader reader;
}
